The invention refers to a bearing arrangement for a differential casing of a differential transmission in an axle transmission light metal casing of a motor vehicle.
In a known bearing arrangement of this type described in German published Application (DE-AS) No. 1,630,902, a long slender axle journal of the differential casing located eccentrically to the two conical roller bearings, with respect to the plane of rotation of the axes of the differential bevel pinions, carries at its outer end the inner race of a conical roller bearing whose outer race is seated in the bearing intermediate sleeve. Because of the long distance between bearings and the small average race diameter of this eccentrically located conical roller bearing, this known bearing arrangement is only suitable for low bearing forces from relatively low-powered motor vehicles. In the known bearing arrangement, the sliding bearing of the driven shaft is located axially in the same diametral plane as the conical roller bearing so that a tubular shaft section departs axially outwards from the shaft section of the driven shaft with sliding bearing support, this tubular shaft section then requiring a further bearing, so that this known bearing arrangement is not directly suitable for swing axles.
In a known bearing arrangement of another type for a commercial vehicle (U.S. Pat. No. 2,563,680), a drive axle is provided with a rigid axle casing of the banjo type in which two side axle tubes depart rigidly from a central flat ring casing body. In order to support the differential casing, which generally also includes the ring gear for engagement with the drive pinion of the cardan shaft, and the two driven shafts, a casing insert inserted in the annular casing body and having two separate bearing eyes is used for the axle journals of the differential casing. Despite the general use of pressed sheet metal parts, this known rigid axle is quite heavy in construction. Neither can this rigid axle be converted without difficulty as a swing axle in the manner usual for passenger cars. One of the reasons why this is not possible is that the inner end of each axle tube is welded to the two sheet metal walls of the double-walled-ring casing body to make a rigid composite. The inner end of each driven half-shaft, on the other hand, has only one single defined bearing position, i.e. a sliding support in the bearing intermediate sleeve in the region of that diametral plane in which is also located the average race diameter of the conical roller bearing which is seated with its inner race on the bearing intermediate sleeve.
In a known bearing arrangement of a different generic type (U.S. Pat. No. 3,202,466) of a steel differential casing of a differential transmission in an aluminum axle transmission casing of a motor vehicle, the axle journals of the differential casing are directly supported in the single-piece bearing eyes by means of conical roller bearings. In a radial reference plane located approximately centrally to the conical roller bearing, the driven shaft has direct sliding support in the axle journal so that a increase in the conical roller bearing so as to accept larger bearing loads is not immediately possible.
An objective on which the invention is based consists essentially in producing a light and compact bearing arrangement of a differential casing of a differential transmission in an axle transmission casing of a motor vehicle for the acceptance of higher bearing loads.
This objective is achieved according to the invention by providing a bearing arrangement of a differential casing of a differential transmission in an axle transmission light-metal casing of a motor vehicle, in which a bearing intermediate sleeve, also in light metal, is inserted so that it cannot move in a bearing eye formed integrally with the axle transmission casing, in which an axle journal of the differential casing is supported by a conical roller bearing, in turn supported on the bearing intermediate sleeve and in which a driven shaft has sliding bearing support by means of a shaft section in a corresponding shaft passage of the differential casing, wherein the inner race of the conical roller bearing is seated on the bearing intermediate sleeve and the drive shaft is additionally supported in the bearing intermediate sleeve by a rolling contact bearing located offset relative to the conical roller bearing in the direction of the bearing axis pointing away from the differential casing.
An advantageous feature in the bearing arrangement according to the invention is that the dimensions of the conical roller bearing are substantially independent of the dimensions of the shaft bearing of the bearing intermediate sleeve and that, because of use of a rolling contract bearing for the steel drive shaft, the bearing intermediate sleeve and also the axle transmission casing can be manufactured from aluminum without troublesome thermal expansions appearing in the bearing arrangement.
In certain preferred embodiments, the roller contract bearing of the driven shaft and a radial fastening flange of the bearing intermediate sleeve are at least approximately located in one radial reference plane of the bearing intermediate sleeve. With this arrangement, the distance between the bearings in the bearing arrangement is advantageously increased for the two support positions of the driven shaft without widening the bearing arrangement overall.
In certain preferred embodiments, the bearing intermediate sleeve has a radial acceptance hole for accommodating parts of a rotational speed sensor, which hole is disposed on the sleeve end opposite the conical roller bearing. This feature makes it possible to use an axle transmission case of the same design for motor vehicles with and without rotational speed sensors on the driven wheels.
In especially preferred embodiments the acceptance hole as the conical roller bearing are located on opposite sides of a radial reference plane through the shaft bearing. With this arrangement, the axial distance between the axle transmission casing and the differential casing is kept as small as possible in each of the directions of the bearing axis.
Finally, the in the case of tandem axles (German Published Unexamined Application - DE-OS No. 2,508,948), it is also known to support the axle journal of the differential casing and the drive half-shaft penetrating the latter by one conical roller bearing each, directly in the single-piece bearing eye of the axle casing, avoiding the use of a bearing intermediate sleeve, the axle casing then having to be split in order to fit the axially inner and larger of the two conical roller bearings.
By means of certain preferred embodiments of the bearing arrangement of the invention the driven shaft has a cylindrical bearing section of a corresponding shaft passage of the differential casing and has splines on its other shaft end continuing axially from the cylindrical bearing section in the differential casing. The bearing section preferably slides directly in the shaft passage. Thus, the shaft bearing of the driven shaft in the differential casing is separated in an advantageous manner from the connection between the driven shaft and the driven shaft bevel gear wheel. By this means, this bearing arrangement is improved and the design of the driven shaft bevel wheel is simplified relative to an arrangement in which the driven shaft is supported indirectly by means of an extended hub of the driven shaft bevel wheel in the shaft passage of the differential casing.
In certain preferred embodiments, the clear width of the bearing eye is at least equal to the maximum diameter of the running surface of the outer ring of the conical roller bearing. This assures that simple assembly of the conical roller bearing is made possible with the smallest possible distance apart of the bearing eyes.
In certain preferred embodiments the apex of the conical angle of the conical roller bearing is located displaced relative to the conical roller bearing in the direction of the differential casing. An O-type bearing arrangement is then provided in advantageous manner.
In certain preferred embodiments the driven shaft has a toothed ring which continues axially from the bearing section of the driven shaft for the shaft bearing associated with the bearing intermediate sleeve. The measuring accuracy of the rotational speed sensor is thus advantageously increased.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.